Orbital nodes

To change manoeuvre target use the right hand icon at the top of the left fleet details pane of the orbital view.

To change the camera focus use the middle icon in the same area.

The orbit will have four "blobs" marked on it, periapsis (closest to orbited object), apoapsis (furthest from orbited body), orbital nodes (where the fleet orbit crosses the plane of the orbit of the manoeuvre target - two nodes).

Using the icons right at the top of the screen adds a reference orbital plane to permit easier estimation of inclination and orbit in the 3d view, plus the lagrange points (useful for parking orbits and for reduced energy injections into/escapes from the gravity well of the larger bodies).